This invention relates to printed circuit board (P.C. board) connections and cabinet wiring for data processing and data handling modules and incorporates inter and intra unit electrical signal connections.
In the past various schemes have been used for making electrical connections to and within electronic units and modules used in computers systems, data handling systems, telephonic and communications equipment and controllers and control systems. Every electronic design involving quantities of electronic components involves a packaging structure of one sort or another. Typically, discrete components such as capacitors and resistors, intergrated circuit chips and MOS chips, including small through large scale intergrated circuits, are mounted on printed circuit boards (P.C. boards) for ease of assembly and handling. These P.C. boards are normally mounted in cabinets, on racks, and electrically interconnected off of the rear or back plane of each board. Such interconnections carry all of the electrical signals between each P.C. board as well as interface signals out of the cabinet, usually through the back panel, to interconnect with other units or with the customer. Early in the development of computer and controller packaging, multiple stand-off pin connectors, pin-socket connectors and ribbon connectors came into popular use.
Previously, each P.C. board had either a ribbon connector formed by parallel strips of solder on the card or had a socket-pin type connector, either of which provided the electrical connection to the back plane of the P.C. board.
Whether a P.C. board ribbon or pin connector is utilized, a row of female connectors is usually mounted to the back panel of the cabinet for receiving each and every possible P.C. board mounted in the unit. Inter-board connections are then wire wrapped from stand-offs associated with the receiving back panel connectors. Large wiring harnesses are built up to carry signals between boards, as well as, to the cabinet interface (input-output) connectors. Signals, as well as, grounds and power supply voltages are also carried through such wiring.
The utilization of such a connection and wiring structure forces certain economic considerations on the manufacturer. Each cabinet or unit must be fully wired at the factory at the time of original construction in order to allow for the expandibility of the unit by the adding of additional P.C. board capability at a later time. The later wiring in individual P.C. board connections is extremely costly, so as to be prohibative. As a result, the manufacturer is forced to supply, and the purchaser pay for, much more wiring, connectors and connector hardware in an expandable, entry level or lower level system than is necessary.
As popular as the above discussed wiring schemes are, they require an expandable module to contain a full compliment of fully wired back panel connectors for handling each and every P.C. board for which the unit is capable, regardless of whether the unit is purchased with that full capability or not. With mass production techniques and economies of scale practices, entry level unit costs have been escalated due to the standardized wiring capability of each unit regardless of whether the customer has a need or even a desire for the expansion capability.
There have also been packaging schemes, where P.C. boards and the attendant wiring thereto can be added, individually, later. These involve a male pin connector attached to the board and a female pin connector is bolted to the back panel. However, when this structure is utilized it is also necessary to bolt the female and male connectors together via their flanges or other protrusions in order to assure that once the P.C. board is connected, it does not accidentally pull free. Such a structure is cumbersome and unpopular as it requires the bolting and unbolting of each P.C. board and/or the disconnecting of user's cables during maintenance which is awkward and time consuming, adding to costs as well as creating a potential hazard when a technician inserts a tool into the cabinet or when cable connections are mixed-up upon reconnection.
An object of this invention is to provide a cabinet and P.C. board interconnection structure which reduces the amount of connection hardware for entry level units having planned expansion capabilities.
A second object of this invention is to provide such an interconnection structure whereby inter P.C. board connections are made off of one edge or plane of each P.C. board while interface (input/output) connections are made off of another edge or plane.
Another object of this invention is to provide such an interconnection structure whereby inter P.C. board connections are prewired into the unit's cabinet at the time of original assembly, the connection apparatus for inter P.C. board connections incorporating a locking mechanism for locking each P.C. board securely in place once it has been inserted.
A further object of this invention is to provide such an interconnection structure where additional back panel interface (I/O) connectors may be easily added after the original assembly, permitting the addition of other P.C. boards to the cabinet in order to enlarge the capability of the unit.
An even further object of the invention is to provide such an interconnection structure where customer or foreign unit interface connectors mount externally to the cabinet back panel, and an assembly and alignment structure enables each P.C. board bearing its individual interface connector to be quickly and correctly inserted and aligned for proper electrical connection with such customer or foreign unit connector and just as easily released therefrom.